Method and apparatus for combustion of residual carbon in fly ash

Abstract

A system for combustion and removal of residual carbon within fly ash particles in which the fly ash particles are fed into an array of process units for combustion. The fly ash particles are subjected to heat and motive air such that as the fly ash particles pass through the particulate bed, they are heated to a sufficient temperature to cause the combustion of the residual carbon within the particles. The fly ash particles thereafter are conveyed in a dilute phase for further combustion through the reactor chamber away from the particulate bed and exhausted to an ash capture. The fly ash is then separated from the exhaust air that conveys the ash in its dilute phase with the air being further exhausted and the captured fly ash particles being fed to a feed accumulator for re-injection to the reactor chamber or discharge for further processing.

What is claimed is: 
     
       1. A method of processing fly ash comprising:
 feeding fly ash to a diverter; 
 diverting a plurality of batches of fly ash to a plurality of separate combustion units, the plurality of batches including at least a first batch, second batch, and third batch, each of the first batch, second batch, and third batch of fly ash independently having an initial carbon content; 
 combusting the first batch in a combustion unit until a desired reduced carbon content is attained, and thereafter removing the combusted first batch from the combustion unit to render the combustion unit available; 
 combusting the second batch in another combustion unit until the desired reduced carbon content is attained, and thereafter removing the combusted first batch from the combustion unit to render the combustion unit available; and 
 combusting the third batch in an available combustion unit before combusting of at least one of the first batch and the second batch is complete.